Shuffling the pack

Microcystis-Ladybower_CCarter

The next group of algae I’m going to consider in my review of higher taxonomy and systematics, the Cyanobacteria, or “blue-green algae”, present some significant challenges.  Not least of these is a shift over the past forty years from being classified according to the rules of botanical nomenclature to being classified according to the International Code of Nomenclature of Bacteria.  The former assumed species could be defined from field material on the basis of morphology, with “type specimens” preserved in herbaria; the latter uses axenic (i.e. pure) cultures as the basic taxonomic unit, and allows a wider range of attributes than just morphology.   In recent years, as those who follow this blog will know, properties such as gene sequences have also been used to define species although the Code of Botanical (now Biological) Nomenclature still requires a description of the any new species that are described, with an expectation that the morphology will take a prominent role in that description.  As this post will show, morphology is no longer such a reliable indication of how Cyanobacteria are organised as it was in the past.

For practical purposes, many Cyanobacteria fall into the same size range as other algae, live in communities that include many protist groups and can be identified using similar techniques as would be employed to identify other algae.  They also have a form of photosynthesis that produces oxygen as an exhaust gas, in contrast to other bacteria which are capable of photosynthesis. This means that a default view of the Cyanobacteria as “algae” is a reasonable starting point for a field ecologist.   However, at an intercellular scale, the Cyanobacteria are very different to other algae, and we should never lose sight of the fact that they actually belong to a different Domain to other algae.

The problems are clear when I compare the morphology-based classification that I used when I first taught classes on algae in 1990 with the classifications that are accepted now.  Then, Cyanobacteria were divided into three or four orders, typically:

  • Chroococcales – single cells or cells loosely-bound into irregular gelatinous colonies
  • Oscillatoriales – filamentous forms lacking heterocysts
  • Nostocales – filamentous forms with heterocysts

The high-level classification, in other words, was based solely on whether or not the organism formed filaments and, if so, whether or not it possessed heterocysts (specialised cells responsible for nitrogen fixation).  This made logical sense when your primary source of insight is morphology.  Unfortunately, more recent studies have shown that it bears little relationship to the genetic relationships amongst the organisms that have been revealed over the past thirty years or so.   A more recent organisation is given in the diagram below.

First, note that this shows subclasses, rather than orders, within the class “Cyanophyceae” (the only class in the division Cyanophyta).   There is rarely unanimity amongst experts on the appropriate organisation of high-level classifications so just bear with me on this one.   Of the four sub-classes, one, Nostocophycidae, contains a single order (Nostocales) which includes all the heterocyst-bearing forms.  No change there.   However, the other two classes diverge very much from the older classifications in that they both contain a mixture of filamentous and non-filamentous forms.

Cyanobacteria_subclasses

The organisation of the Cyanobacteria (blue-green algae) division into four sub-classes.  Filled boxes indicates the classes that are represented in UK and Irish freshwaters.   Organisation follows Algaebase.   The image at the top of this post shows a Microcystis bloom at Ladybower Reservoir (photo: Chris Carter)

The Oscillatoriophycidae is a good example, with five sub-classes, four of which are represented in the UK and Ireland.  Two of these have featured in several posts (see Appendix) so you can see for yourself just how different they are in appearance.  The Oscillatoriales includes filamentous forms without heterocysts whilst the Chrococcales has taxa that either exist as single cells or in masses loosely-bound within gelatinous colonies.    A similar situation exists within the Synechococcophycidae; indeed, some genera that would formerly have been considered to be relatives of taxa within Oscillatoriales (e.g. Schizothrix and Heteroleibiana) are now included in families in this group.   There is, however, still more work to be done to unravel all the relationships within this sub-class.   The current understanding is that there is a single order (“Synechococcales”) but a great number of families.  Similarly, all the heterocystous forms are grouped into a single order, the Nostocales, within the Nostocophycidae, also divided into a large number of families.

Oscillatoriophycidae_orders

Organisation of the Oscillatoriophycidae showing the orders that include genera found in UK and Irish freshwaters.  

I always stress that taxonomy and identification are two distinct crafts: the taxonomist calls on a wide range of tools to find natural groupings of species at different levels whilst an ecologist only needs a parsimonious route to an unambiguous identification.  For the purposes of identification, recognising whether an organism is filamentous or not is a logical early step, even though both options will contain representatives of both Oscillatoriophycidae and Synecchococcophycidae.   We need to recognise that some of the characteristics that contribute to our taxonomic understanding (gene sequences, arrangement of thylakoids) are useless from the point of view of someone trying to name an organism encountered in a field sample but, at the same time, the taxonomist’s standpoint will not necessarily capture all of the features that explain how an organism contributes to energy and nutrient flow within ecosystems.

Calothrix-stagnalis_CCarter

Calothrix stagnalis: a member of the Nostocales.  Note the heterocysts at the base of the filaments (photo: Chris Carter)

References

Mai, T., Johansen, J.R., Pietrasiak, N., Bohunciká, M. & Martin, M.P. (2018).  Revision of the Synechococcales (Cyanobacteria) through recognition of four families including Oculatellaceae fam. nov. and Trichocoleraceae fam. nov. and six new genera containing 14 species.  Phytotaxa 365: 1-59.

Palinska, K.A. & Surosz, W. (2014).  Taxonomy of cyanobacteria: a contribution to consensus approach.  Hydrobiologia 740: 1-11.

Appendix

Links to posts describing representatives of the major groups of Cyanobacteria found in freshwaters.  Only the most recent posts are included, but these should contain links to older posts (you can also use the WordPress search engine to find older posts).

Group Link
Synechococcophycidae  
Synechococcales Chamaesiphon: A bigger splash

Heteroleibleinia: River Ehen … again

Oscillatoriophycidae  
Chrococcales Aphanothece: No excuse for not swimming …

Gloeocapsa: The mysteries of Clapham Junction …

Oscillatoriales Microcoleus: How to make an ecosystem

Oscillatoria: Transitory phenomena …

Phormidium: In which the spirit of Jeremy Clarkson is evoked …

Pleurocapsales Watch this space …
Spirulinales Watch this space …
Nostocophycidae  
Nostocales Nostoc: How to make an ecosystem (2)

Rivularia: Both sides now

Scytonema, Stigonema, Tolypothrix: Tales from the splash zone

   

Some other highlights from this week:

Wrote this whilst listening to: Leonard Cohen’s posthumous album Thanks for the Dance.   And, as I used it to name a post, Joni Mitchell’s Both Sides Now.

Cultural highlights:  David Hockney: Drawing from Life at the National Portrait Gallery.   Great examination of the importance of drawing and observation to artistic practice.   By coincidence, another post I’ve cited is named after one of Hockney’s paintings

Currently reading: Robin Wall Kimmerer: Gathering Moss (Oregon State University Press).  A collection of essays on the natural and cultural history of mosses.

Culinary highlight: dinner at The Sichuan on City Road in London.

Hockney_drawings

Rhapsody in red

Audouinella_Oxbow_Dec19

On an overcast winter day with just a sprinkling of snow on the fells the Lake District can appear very monochrome.  Look closely at the bed of some rivers, however, and you are confronted by a much more vibrant palette with browns, greens and reds vying for your attention.  Somehow, paradoxically, the stream algae are at their most prolific and vigorous when the rest of Cumbria’s biological diversity has hunkered down to wait for the onset of Spring.

One of the most conspicuous groups at this time of the year are the red algae.  The green algae, diatoms and cyanobacteria are there all year round, even if winter is the time when they are most abundant.  The red algae, however, are barely evident – and certainly not to the naked eye – during the summer months.   It is only when autumn is well underway that the first blushes of pinkish red appear on the stones lining the beds of rivers.   This is in contrast to the red seaweeds which can be found on our coasts all year round, and indeed, to the many red algae that inhabit warm tropical seas.  What is so different about red algae in streams that leads them to favour the colder periods of the year?   What is it about streams, too, as I rarely see red algae in lakes (Batrachospermum is the exception: see “More algae from Shetland lochs”)?

This post will not answer those questions, but will give a quick overview of the red algae we find in freshwaters, in the manner of an earlier post about green algae (see “The big pictures …”).   The table below shows the systematics of the red algae, following a molecular phylogeny study by Hwan Su Yoon and colleagues from 2006.   There are two sub-phyla, of which one, Cyanidophytina, has no representatives recorded from the UK or Ireland.   There are just eight species in this group of primitive red algae, associated mostly with extreme environments.

The other subphylum, by contrast, has over 7000 species, divided between six classes, but 94 per cent of these are marine.   There are just thirteen genera of red algae recorded from freshwaters in the UK and Ireland, but spread amongst five of these six classes.   This seems to suggest that an ability to thrive in freshwaters has evolved several times during the evolution of this group.

Rhodophyta_classes

The organisation of the red algae (Rhodophyta) showing division into two subphyla and seven classes.  Pink fill indicates the classes that are represented in UK and Irish freshwaters.   Organisation follows Algaebase and Yoon et al. (2006).    The photo at the top of this post shows Audouinella hermainii in the River Ehen, Cumbria, in December 2019.

Of the five classes that do have freshwater representatives, well over half of the genera and species recorded from the UK and Ireland are found in the Floridiophyceae.   This class has over 6900 species (95% of all red algae) split between 34 orders, of which five contain genera found in UK and Irish freshwaters.   Of these, the Batrachospermales, one of the few red algal orders that is exclusively freshwater, contains five genera and eleven species, whilst the other four contain just one genus each.

The Batrachospermales contain two morphologically-distinct groups of genera: Batrachospermum, Sheathia and Sirodotia form one of these, whilst Lemanea and Paralemanea form the other (see links below for more details and images).   Whilst we have molecular evidence that suggests that the Batrachospermales are a natural group, it is hard to point to a single characteristic that helps someone more interested in identification than taxonomy.   In fact, it is the life-cycle that is most distinctive (“… diplohaplontic … heteromorphic and contains a reduced tetrasporophyte”) but few of us are as well-schooled in algal life-cycles now as our predecessors were (see “Reflections from the Trailing Edge of Science”).   A hundred years ago, we would have had to rely upon the same limited set of morphological characters for both identification and taxonomy; now the taxonomist’s toolkit has expanded considerably whilst identification is still mostly reliant on features we can see with the naked eye or a light microscope.  For the red algae, this is still mostly enough to answer questions about what species we have found but unravelling the logic behind a classification may need a broader perspective.

Florideophyceae_orders

Organisation of the Florideophycae showing the orders that include genera found in UK and Irish freshwaters.  

 

References

Entwisle, T.J., Vis, M.L., Chiasson, W.B., Necchi, O. & Sherwood, A.R. (2009).  Systematics of the Batrachospermales (Rhodophyta) – a synthesis.   Journal of Phycology 45: 704-715.

Yoon, H.S., Müller, K.M., Sheath, R.G., Ott, F.D. & Bhattacharya, D. (2006).  Defining the major lineages of red algae (Rhodophyta).  Journal of Phycology 42: 482-492.

van den Hoek, C., Mann, D.G. & Jahns, H.M. (1995).  Algae: an Introduction to Phycology.  Cambridge University Press, Cambridge.

 

And some other cultural highlights from the week:

Wrote this whilst listening to: Dave’s Psychodrama,

Cultural highlights:  Dave’s performance of Black (from Psychodrama) at the Brits Award Show.  I would not normally have watched this but was stuck in a hotel room with no wifi reception and was totally blown away by the power of his performance.

Currently reading: Bill Bryson’s The Body

Culinary highlight: I’m trying to cook one meal each month using only UK-sourced ingredients, in order to help me focus on seasonal cycles.  My February effort was a beer and cheese fondue: very easy to cook, using beer from about 500 metres from my house (Durham Brewery’s Evensong) and a mixture of Cheddar and Lancashire cheeses from Durham Indoor Market.

 

Appendix

Links to posts describing representatives of the major groups of red algae found in freshwaters.  Only the most recent posts are included, but these should contain links to older posts (you can also use the WordPress search engine to find older posts).

Group Link
Bangiophyceae Watch this space …
Bangiophyceae Watch this space …
Compsopogonophyceae Watch this space …
Florideophyceae  
Achrochaetiales Something else we forgot to remember
Balbianiales The Hilda Canter-Lund prize
Batrachospermales Lemanea: The complicated life of simple plants

Batrachospermum: More algae from Shetland lochs

Hildenbrandiales More about red algae
Thoreales Watch this space
Porphyridiophyceae Watch this space …
Stylonematophyceae More pleasures in my own backyard

Policy-based evidence?

In my day job as an ecologist I spend a lot of time thinking about how energy and nutrients flow through ecosystems.  Understand this and it should be possible, in theory, to provide guidelines for how we move to a more sustainable future.  However, communication of ecological principles is often a frustrating business, especially when your audience is government officials balancing scientific evidence with other policy concerns.   The organisations I work for pay lip-service to “evidence-based policy” yet, somehow, fail to react in the way I expect when confronted with strong evidence.

Some of my frustration, I realise, comes from not fully understanding how evidence moves through the complex human ecosystems of government agencies, the businesses whose actions they regulate and the stakeholders whose lives are affected by decisions. I’ve written about this before (see “The human ecosystem of environmental management” and subsequent posts) and find that ecological cycles can form powerful metaphors for understanding information flow and, as a result, how we can communicate important results.   It also, as I will show, helps us understand when to recognise that the argument does not hinge on scientific evidence but on powerful institutional barriers.

The graph at the centre of the diagram below comes from a paper that I co-authored as part of my work with the European Commission and describes the relationship between aquatic plant communities (“Macrophyte EQR”) and total phosphorus in shallow lakes in north-west Europe.  It formed part of a bigger project to help Member States set environmental standards.    The point of my diagram is to show how ecological evidence (represented by our graph) is nested within a series of other considerations which often lead to the decision the evidence points towards being over-ruled.

target_diagram

Regulation in the face of noisy ecological data: ring 1 represents environmental targets; ring 2 is the regulatory framework; ring 3 is national policy (water pricing and the cost recovery framework in particular) and ring 4 is society’s environmental aspirations.

The process works something like this: ecology is not an exact science, but we could use this graph to justify a maximum permitted total phosphorus concentration of about 60-70 micrograms per litre in these lakes (1: the innermost ring).   This, then, converts into a series of consents and licenses for businesses that discharge into the catchment and, potentially, into encouragement for farmers to sign up to countryside stewardship schemes (ring 2).  The carrots and sticks that make up this regulatory framework then fit into a broader framework of environmental management that embodies the “polluter pays” principle (ring 3).  Finally, this broader framework reflects, to a greater or lesser degree, society’s aspirations for the environment (ring 4).

Protecting and restoring lakes and rivers, then, depends on society as a whole regarding the environment as a high priority (4) and being prepared to pay for this (3).  We could refer to this as an effective environmental aspiration*, as distinct from everyone talking the talk on social media but carrying on with unsustainable practices in their everyday lives.  Once people recognise their own agency, then the “polluter pays” principle should be easier to enact and utility companies will be less inclined to challenge the regulator because they know they can recover their costs (2).

If, on the other hand, the link between rings 4 and 3 is weak, and that there is pressure to reduce utility charges (as is the case in the UK at the moment for reasons that go beyond the subject of this post), then decisions within individual catchments will be less straightforward and the targets themselves will become the subject of greater scrutiny.

The graph at the centre of the diagram is typical of the evidence that we have to use in situations such as these.   There is not a perfect relationship between biology and nutrients (only 43% of the variation in EQR is explained by total phosphorus) so it is hard for catchment managers to tell stakeholders that a reduction in phosphorus loading will definitely lead to an improvement in ecology.  Ecologists never work with the certainty of engineers; we deal in probabilities.  We can say that if this reduction was enacted across the whole country then many lakes would show improvements but may be hard to be specific on a local scale.   Given the costs involved in producing these reductions, the temptation is to play safe.

Playing safe starts with the graph itself.   If you can only explain a proportion of the variation in Y from X then there are, invariably, loose threads that can, with a little tugging, unravel the argument.  In this particular case, there is a substantial body of experimental evidence behind the relationship but, even so, the targets derived from these relationships often translate into significant challenges for both regulators and regulated.    It is often far easier to kick the can down the road: easily achieved these days by prioritising other tasks for the limited pool of technical specialists employed by our environmental agencies.

I started this post by drawing metaphors from ecology in order to understand the process of environmental management.  The analogy I see here is that of equilibrium: imagine the barriers between the rings as a series of membranes: society’s aspirations flow towards the centre and, if these are high and all the intermediate stages are in equilibrium, then our graphs are powerful evidence for moving towards a healthy, sustainable environment.  As soon as there is disequilibrium (e.g. high environmental standards versus a low willingness to pay for improvements in utility infrastructure), however, all the intermediate steps become adversarial rather than consensual and the noise inherent in ecological relationships becomes a pawn in political and bureaucratic games.

* analogous to the economist’s concept of “effective demand”

Reference

Poikane, S., Phillips, G., Birk, S., Free, G., Kelly, M. G., & Willby, N. J. (2019). Deriving nutrient criteria to support ʽgoodʼ ecological status in European lakes: An empirically based approach to linking ecology and management. Science of the Total Environment, 650. https://doi.org/10.1016/j.scitotenv.2018.09.350

 

This week’s other highlights:

Wrote this whilst listening to: Jeff Beck Group’s Beck-Ola from 1969.   (Just bought tickets to see Jeff Beck at the Sage in May, so celebrations were in order).

Cultural highlight:  The Strange Case of Charlie Chaplin and Stan Laurel at Northern Stage in Newcastle, during which I was hauled up on stage to play piano (photo below).   I can’t play piano but they showed me what two notes to play and when.   Figured that if I can’t face this, then I shouldn’t have signed up to a live microscopy “performance” at Green Man this summer.

Currently reading:  Brooklyn by Colm Toíbín

Culinary highlight: a self-baked lime and coconut drizzle cake.

Playing_piano_at_Northern_Stage

And the Oscar for best alga in a supporting role goes to …

Low_Force_022006

I know that the focus of this blog can meander, depending on what takes my fancy week-to-week.  My core business is, however, writing about the hidden world of algae so, having written about Sam Mendes’ use of the River Tees Upper in his film 1917 in my previous post, I thought that I ought to take a trip up Teesdale to take a closer look at what is growing in the river at this time of year.   With Storm Ciara looming ominously on the forecast, I knew that if I did not sacrifice my Saturday morning it might be a while before I had another opportunity (there’s a graph at the end of this post which confirms this hunch).  And so I found myself buffeted by the wind with clouds scudding across the sky and the peaty water of the Tees thundering across the sequence of cascades that make up Low Force.

The main river was, even after a period without much rain, too deep and fast-flowing for me to venture far in so my activities were confined to the margins.   The rapid current, however, means that there were few of the small and medium-sized stones that I would normally remove and inspect.  Most had been picked up and transported further downstream leaving wide expanses of the Whin Sill bedrock.   In the shallow areas towards the edges that were not exposed to the full force of the current, there were dark green patches that I picked at with a pair of forceps.   When I was able to look at these under my microscope, I saw that they were Ulothrix zonata, a common inhabitant of northern British streams during the winter, and an alga that I have written about previously (see “The intricate ecology of green slime …” and “Bollihope Bhavacakra” amongst others).

Ulothrix_zonata_Tees_200208

Ulothrix zonata growing on Whin Sill in the River Tees at Low Force, Teesdale in February 2020.   The upper and central pictures on the left hand side show vegetative filaments and the lower picture shows empty cell walls after zoospores had been released, to which a germling is attached.  Scale bar: 20 micrometres (= 1/50thof a millimetre).   

The rocks were very slippery, even when not covered by green patches of Ulothrix zonata.   My usual approach to collecting specimens is to remove the whole stone and scrub the top surface with a toothbrush.  That, however, was impossible here so I had to resort to brushing the surface of the Whin Sill and hoping that enough of the slippery film remained attached to my toothbrush, which I then agitated in a bottle containing some stream water to shake the gunk off before repeating the process.  The small amount of material that I did manage to transfer from the rocks imparted a chocolate-brown hue to the water that signifies that diatoms were present.

Sure enough, when I did get a drop of the suspension under my microscope, there were diatoms aplenty, mostly wedge-shaped cells of Gomphonema growing at the end of long, branched mucilaginous stalks.  These, like Ulothrix zonata, are very common in northern British streams at this time of year.  I described similar assemblages from the River Wear at Wolsingham although, in that case, the Gomphonema shared their habitat with motile Navicula species as well (see “The River Wear in January”).   The Gomphonema in the River Tees is most likely G. olivaceum or a relative but I will need a closer look to be sure.  If I used an old Flora such as Hustedt’s 1930 Süsswasser-flora Mitteleuropas, I would have been able to be more assertive in naming this “Gomphonema olivaceum” but we now know that diatom systematics are more complicated than was thought to be the case in Hustedt’s days.

Gomphonema_Tees_200208

Gomphonema olivaceum-type colonies growing on Whin Sill in the River Tees at Low Force, Teesdale, February 2020.  Scale bar: 20 micrometres (= 1/50th of a millimetre).   

The sequences of 2017 were filmed in June not January so George Mackay would not have found the bedrock of the Tees to be quite as slippery as it was on my visit.   As the water warms up, grazers become more active and, as a result, the biofilms in the summer are much thinner than those in January.  That means that fewer slippery, slimy polysaccharides are produced, making it easier to keep your balance when walking at the edges of the river.

As I mentioned in my previous post, the sequence in 1917 involves George Mackay falling into a river in Picardy but crawling out of a river in Upper Teesdale.   I know less about the rivers of Picardy than I do about those in northern England, but a combination of low relief, extensive canalisation and the presence of heavy industry and coal mining in the area will mean that the algae found there will be very different to those in the Tees.   However, if 1917 can get 10 Oscar nominations (including for best sound editing) despite having the call of a Great Northern Diver echoing over No-man’s Land, then we can be fairly sure that the Wrong Sort of Algae is a level of detail that Sam Mendes and Roger Deakins thought they could safely ignore.

References

You can find some information about the diatoms of Picardy rivers in this paper:

Prygiel, J. & Coste, M. (1993).  The assessment of water quality in the Artois-Picardie water basin (France) by the use of diatom indices.  Hydrobiologia 269: 343-349.

This week’s other highlights:

Wrote this whilst listening to:  Michael Kiwanuka and other acts who will be playing at the Green Man festival in August.   I’ll be there too, talking about slimy algae, at Einstein’s Garden, the on-site science festival, along with (I hope) a gang of volunteers from the British Phycological Society.

Cultural highlight:   Two picks this week.  The first was Monteverdi’s Vespers performed at Durham Cathedral.  The cavernous interior of the cathedral joins the choir and orchestra as part of the experience, providing resonances that raise the experience beyond anything that a CD can offer.   The second is Bong Joon-ho’s film Parasite, a strong contender, along with 1917, at this evening’s Oscar Awards Ceremony.

Currently reading:  John le Carré’s Mission Song

Culinary highlight: a Napoli pizza cooked with locally-grown flour (www.gilchesters.com), part of a push this year to source more of our ingredients locally.  There’s obviously more to a Napoli pizza than can be grown in the UK but it is a start.

Tees_Middleton_levels_200208

River levels at the Tees at Middleton-in-Teesdale (x km downstream from Low Force) in the week from 3 to 9 February 2020. The arrow shows the time of my visit; note the steep rise in level a few hours later, coinciding with Storm Ciara moving through the region.  Graph from the excellent https://riverlevels.uk website.

1917 and all that

low_force_HAK

If you haven’t seen it already, Sam Mendes’ film 1917 is well worth a trip to the cinema, particularly for the way it appears to have been filmed as a single take, which gives it a very immersive view of the brutality of trench warfare.   The result is a sense that we, the audience, are there alongside the protagonists that lasts up until the point when a small detail intrudes to break the spell and you find yourself sitting up and wondering what is going on.   This may be, I admit, a niche concern but, for me, this happens at the point at which the lead character, played by George Mackay, jumps into a quiet, slow-flowing canalized Picardy river to escape a pursuer.   As he enters the water, it transmogrifies into a fast-flowing rapid-strewn torrent, through which he struggles to keep his head above water until eventually crawling out onto rocks beside some woodland and, from there, back into Picardy and the trenches.

Was it just me, or was that an outcrop of Whin Sill in the background as Mackay thrashes around trying to keep his head above water?   I am no geologist but I had passed signs warning walkers that filming was taking place as I drove up Teesdale a few months ago and the rumours were that this was a location for a major film.  I guess even a geological dunce can start to recognise geological formations when he has seen the paraphernalia of a film set at precisely the point on the River Tees where Whin Sill outcrops create a cascade waterfall.

1917_location_low_force

Filming 1917 at Low Force, Teesdale, June 2019.   The photo at the top shows Low Force on the River Tees (credit: Heather Kelly)

I am not alone.  A listener to Simon Mayo and Mark Kermode’s film programme on BBC Radio 5 wrote in to say that he had been discombobulated by the sound of a Great Northern Diver as, earlier in the film, Mackay and a fellow soldier had made their way across No Man’s Land.   The listener pointed out that the closest locations where the Great Northern Diver was found was northern Scotland, and that the haunting call of this bird appearing out of place had jarred with the film’s otherwise close attention to period detail.   A few years ago, I had a similar experience in a performance of Alan Bennett’s A Question of Attribution when a backdrop supposed to represent the Queen’s picture gallery at Buckingham Palace included Leonardo da Vinci’s Lady with an Ermine, which I knew to belong in a gallery in Krakow.   Such details can undo the hard work of cast and crew to create a particular atmosphere.   Instead of being immersed in the drama, you find yourself scratching your head and asking questions that the director had never anticipated.

As I said above, this is all very niche stuff.  A few ornithologists will have noticed the wrong birdsong (strange synchronicity to use that word in a post about trench warfare), almost everyone else will have benefited from the haunting call’s contribution to the overall atmosphere. And a very few river ecologists will have been disconcerted by the seamless transition from Picardy to Teesdale and back.  Everyone else (the vast majority) will have been grateful that Sam Mendes did not let Mackay float in a muddy, almost stationary French canal while German soldiers took potshots at him, and thus depriving the story of any sense of resolution.

There are, almost certainly, far more occasions when a wrong detail passes right over me than when I am discombobulated by something that I do notice.  Any kind of specialist knowledge will reveal small incongruities that a film crew did not realise mattered (they probably don’t in the grand scheme of things) or which were deliberately changed to heighten an effect (as Mendes did in 1917).   The few that notice will be temporarily sprung from the world of illusion that the director has striven to create but, for everyone else, the magic will be heightened.   We should, really, be grateful that Sam Mendes didn’t worry too much about a realistic depiction of the hydrology of Picardy.

This week’s other highlights:

Wrote this whilst listening to: Beethoven’s 9th Symphony. What else at this sad time?

Cultural highlight: Welsh harpist Caitrin Finch playing with Colombian band Cimarron at the Sage, Gateshead on Saturday night.

Currently reading:  The Memory Keeper’s Daughter by Kim Edwards

Culinary highlight: a sociable evening cooking Sichuan food with Heather and Rosie, recreating some of our favourite dishes from our trip to Chengdhu last year using Fuchsia Dunlop’s cookbook.   Consumed with two bottles of Durham Brewery’s Smoking Blonde ale